Budget for camera
Many will agree that photography is not a cheap hobby, especially for D-SLRs or larger format cameras. As one gets more into photography, one can get more and more obssessed with getting more and better equipment. And end up spending more and more.
So one should set a budget about how much to spend for all equipment in the next 10 years. This will help one to plan what to buy more carefully. Overspending is the culprit of our current economy and our personal/family woes.
To start off, for most people, buying camera and lenses is not an investment. They depreciate as soon as you opened the box. The exception is for those who can use these equipment to make more money than they spend on the equipment.
Personally I learn not to spend more than 3 years salary on a house and not to spend more than 3 months salary on cars. For camera equipment, I suggest not to spend more than 1-2 weeks salary. If you are buying a D-SLR, once you have decided on your total budget, then divide the budget into thirds, 1/3 for the camera body, 2/3 for the camera lenses and accessories.
Then you decide why you need to upgrade your current camera. You need to pinpoint the technical limitation missing in your current camera. "I just want to take better photos" is not useful at all. On the other hand, if your camera missed the low light action shots, then you know you need to get a camera with better high ISO performance, brighter and faster lens, etc. Once you know what you need, you shop around to get everything you need under your budget.
If that exceeds your budget, then you should defer buying the new camera. You can consider putting your budget money into real investment and grow the budget, or use your photography skill to make some money with your current camera to raise enough fund to get what you need. While your money is growing in investment, you continue to refine your technique and push the limit of your current camera.
I found that many people don't know what they need and end up buying a slightly better upgrade of their current camera which still cannot do what the current camera fails to do. An example will be having a PS camera that fails to capture low light sports action. One finds out the needed D-SLR and fast lens are too expensive, so buys the entry level D-SLR and slow kit lens only to find out that this setup still fails to capture the low light sports action.
So research carefully on what you need and budget yourself wisely.